Vapor Barrier For Blown In Insulation

Adding a second vapor barrier could cause condensation to become trapped in the insulation between the two vapor barriers.

Vapor barrier for blown in insulation.

Settlement vapor barriers condensation r values voids this document assists building buyers owners or inspectors who need to diagnose identify or improve building insulation for new construction or retrofit and energy savings projects. A common misconception is that all insulations require vapor barriers in all situations. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall.

If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. Attic insulation should always be installed with the paper backing facing toward the living space the ceiling in this case. Usually composed of a thin film such as polyethylene vapor barriers are used to retard or prevent water vapor diffusion into a wall ceiling or floor during the cold winter. Cima does not recommend the use of vapor barriers with cellulose insulation except in circumstances of exceptionally high moisture levels such as an indoor pool facility or very cold climates.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Not every wall does. Research has shown that this is incorrect.